Steam engine



'3 Sheets-Sheet 2.

(No Model.)

T. L. DENNIS. STEAM ENGINE.

(80 Model.)

' I 3 Sheets-Sheet 8. T. L. DENNIS. STEAM ENGINE.

Patented Mar. 1,1887,

'UNITED STATES PATENT Fri-on THOMAS L. DENNIS, OF SOMERVILLE, ASSIGNOROF ONE HALF TO LABAN DENNIS, OF NEWARK, NEW JERSEY.

STEAM-ENGINE.

SPECIFICATION forming part of Letters Patent No. 358,598, dated March 1,1887.

Serial No. 208,391. (No model.)

To all whom it may concern:

Be it known that I, THOMAS L. DENNIS, a citizen of the United States,residing in Somerville, Somerset county, New Jersey, have inventedcertain new and useful Improvements in Steam-Engine Out-Offs, fullydescribed and represented in the following specification, and theaccompanying drawings,forming a part of the same.

This invention relates to a device in which separate slide-valves arefitted to the induction-ports and are operated by detachable tappets,which are controlled by the governor; and the invention consists partlyin the construction and arrangement of the slide-valves andcylinder-ports, and partly in the construc tion of the cut-offmechanism, all substantially as hereinafter set forth.

In the drawings, Figure 1 is a side elevation of an engine provided withmy improvement. Fig. 2 is a plan of part of the cylinder and cutoffmechanism on a larger scale, the parts being shown in section, wherehatched, at the center line of the cylinder, with a false valve seat.Fig. 3 is a side elevation of the same with the steam-chest coverremoved. Fig. 4 is a plan of the valve-seat. Fig. 5 is a view of theface of the valve. Fig. 6 is a side view of one of the valves, and Fig.7 is a cross-section of the same with part of the cylinder and the falsevalveseat on line a; a: in Fig. 5.

A is the bed of the engine; B, the steamcylinder, and G the connectingrod to the crank O.

D is the crank-shaft carrying an eccentric, D, which serves, by the useof any valve-cutoff mechanism, to operate two separate slidevalvesindependently and to out OK the steam at any desired point in thestroke.

The valve-seat E is provided with two in-- duction-ports, a a, and withtwo eductionports, I) I), each opening into the seat adjacent to one ofthe ports a or a. The seat is raised above the steam-chest seat S, sothat the steamvalves may receive steam from the edges of the seat, andthe ports b b are united in an exhaust-outlet, b and are each connectedalternately with the adjacent inductionport by the arch c in a flatD-valve, V.

. The steam-chest T is fitted to the seat S and provided with a cover,T, and a stuffing-box for the valve-rod.

The valves V are each provided with a cover, d, which forms a chamber, eover the back .of the valve for connecting the ports a a with thesteam-supply which enters the chest by pipe U,or at any convenientpoint. The chamber has several openings through the valveface to receivethe steam from the chest and to lead it into the induction-port, theopening 6 corresponding 'in size and communicating with the port a or a,and the openings 6, formed one at each side of the arch a, communicatingwith ports 8, formed in the surface of the valve-seat and receivingsteam from the interior of the chest by passages 8. These passages areshown in Fig. 7 as opened into the edges of the valve-seat, which ismade narrower than the lateral walls of the chest, to afford the steamaccess thereto.

The openings 6 are shown in the drawings about equal in area to thepassage 6, and the steam passes upward through the former and downwardthrough the latter. Its pressure upon the valve may thus besubstantially balanced,and the frictional resistance of the valve maybe-diminished or regulated in any desired degree.

These valves are provided with separate concentric valve rods m and n,the former passing through the latter, and each being provided beyondthe stuffing-box S with a dog, it, by which it is independently moved.Such movement is effected by the regular reciprocating motion of aslide, G, which is actuated by a connection, D to the eccentric D. Theslide is furnished with two tappets, q, pivoted at its middle andprojected toward the dogs 70, and with two lugs, o, for positivelyshifting the valve to open the exhaust at the end of each stroke. Thetappets and lugs project from the slide toward the valve-rods and theirattached dogs, and shift the valves in either direction when engagedtherewith. The tappets are also furnished with inclined arms q,projecting from the opposite side of the slide toward a cutoff stop, f,which is actuated by the governor, and serves to detach the tappets fromthe dogs at the required point in the stroke.

The governor shown at h in Fig. l is represented as mounted upon theguides p, which sustain the slide G, and the rising of thegovernor-balls y, when the engine increases in speed, serves to pressthe stop f toward the slide and to intercept the inclined arms q earlierin the stroke. The contact of the arm with the stop operates to move thearm and tappet upon their common pivot and to withdraw the tappet fromthe dog, as shown in Fig. 3. When the dog is thus released from thetappet, the valve -rod is immediately shifted to close the valve bymeans of a spring, t, applied to the rod between the guide 2) and thedog.

The valve connected with the tubular valverod a is shown in Fig. 3 thusshifted, the amount of movement effected by the spring being indicatedby the projection of the tappet beyond the shoulder with which it wasengaged upon the top of the dog.

The springs are adjusted to move the valve freely until theinduction-port of the cylinder is closed, as shown in the valveconnected with the rod m, the unbalanced pressure upon the back of thevalve or its cover then serving to increase the frictional resistance ofthe valve and to prevent its shifting still farther into a positionwhere the exhaust would be opened. The further movement required to openthe exhaust is eiTect-ed positively at the end of each stroke by the lug0, the tappet engaging with one side of the dog when the lug pressesupon the other, as shown in the dog upon the valverod m.

The slide G is shown at the extreme lefthand end of its stroke with onevalve (that on the rod in) wholly shifted by the lug 0, and the other(that on the rod n) closing over the iuduction-port ct by the action ofthe spring t. A stuffing-box, n, is applied to the end of the hollowvalve rod n, to prevent leakage around the rod, and the dogs are securedadjustably upon the valverods, as by nuts o, to permit the adjustment ofthe valves.

It is obvious that with this construction the point of cut-off may bevaried indefinitely by the automatic action of the governor, and as thevalves, by the construction of the valvecover d and its openings 0 e,may be very nearly balanced upon the seat S, the movement of the dogsand the tappets may be effected with very little strain upon the latter,and the entire mechanism operate as efl'ectively as the valve-gearingcommonly applied to a Corliss engine. My invention therefore affords, bythe combination of the balanced D-valves and the independenttappet-connections with the slide and eccentric, a substantialequivalent at much less expense for the hi ghlyapproved Corlissvalve-gearing.

A special advantage in my construction is that the valve mechanismaffording these advantages may be readily substituted for that of anyother slide-valve and eccentric upon an engine unprovided with acut-off. In such case the ordinary three-ported valve-seat may bereadily converted into a four-ported seat, such as is required for myindependent D- valves by applying a false valve-seat. Such aconstruction is shown, for illustration, in Fig. 2, where the seat S isshown provided upon its outer face with the four ports to operate withmy improved valves, and upon its inner face with three ports to fitthose upon the original cylinder-seat S.

It will be noticed that my invention differs from others in which twovalves are operated over separate induction-ports, as a a, in movingtoward one another independently and alternately when the valve opens atthe commencement of the stroke to admit steam to the cylinder. Such amethod of operation arises from the particular construction andarrangement of the tappets and the lugs which are affixed to theeccentric slide G to actuate the valves, and which thus efl'ectsubstantially the same result as the tappets and cut-oif-releasemechanism employed in the Corliss Valvemotion.

My invention may be cheaply applied to either new or old engines, andeffects a very material saving in the consumption of steam when appliedto the latter.

I am aware that it is not new to balance a slide-valve by making achamber over the back and openings in the face, as shown herein, andthat two independent valves have been actuated by concentric valve-rodssimilar to mine. I do not therefore claim either of such constructions,broadly, but have shown the advantage of combining the balanced D-valveof simple construction with the particular class of cut-off mechanismwhich I employ, and which would not be so durable or operative with aheavily-loaded slide-valve.

Having thus set forth my invention, what I claim, and desire to secureby Letters Patent, 1s-

1. The combination, with a cylinder valveseat, S, having two inductionand two eduction ports, arranged as described, of two D- valves providedwith concentric valve-rods, and dogs applied to such valve-rods andactuated by detachable connections, as tappets q, to a reciprocatingslide G, substantially as herein set forth.

2. The combination, with a cylinder valveseat, S, having two inductionand two eduction ports, arranged as described, of two D- valves providedwith concentric valve-rods, and dogs applied to such valve-rods andactuated by an eccentric slide, G, provided with lugs 0, and tappets q,having arms q, actuated by a governor-stop, substantially as herein setforth.

3. The combination, with the valve mechanism constructed substantiallyas herein described, of a detachable valve-seat provided with four portsupon one side terminating in three po r'tsupen the opposite side,adapted to of the valve, communicating with the inletfit a three-portedvalve-seat, as and for the ports a a andthe ports s, as and for thepurpurpose set forth. pose set forth.

4. The combination, witha cylinder valve- Intestimony whereof I havehereun set 5 seat, S, having two induction-ports, a a, and my hand inthe presence of two s'ubscnbing 15 two eduction-ports, bb,arranged asdescribed, witnesses.

of lateral passages s, communicating with the THOMAS L. DEN N IS.steam-chest and with the ports 8 upon the withessesz. valve-seat, andtwo D-valves having each a THOS. S. CRANE,

10 cover, (1, forming a chamber, a, over the back HENRY J. MILLER,

